The present invention relates to an opto-electroactive device comprising a metallocene. More particularly, the present invention relates to an opto-electroactive device comprising a metallocene of the general formula (η5-C5R5)2MX2, wherein M is zirconium or hafnium.
Common examples of opto-electroactive devices include electroluminescent devices, OLEDs, photovoltaic devices, and the like. In many examples opto-electroactive devices comprise a light-emitting or light-absorbing layer. In other examples opto-electroactive devices comprise a hole-blocking layer. A hole blocking layer usually comprises a material, typically an electron transporting material, that is effective in blocking transport of holes through the said layer, thus increasing the possibility of electron-hole recombination as well as confining recombination within desirable layers. An effective hole blocking material is one for which the ionization potential of the material is at least slightly larger than the ionization potential of the adjacent emissive layer. In a particular example the hole blocking material has an ionization potential at least about 0.1 eV larger than the ionization potential of the adjacent emissive layer. Such materials of the hole blocking layer also preferably have high electron transporting properties, such as a high electron mobility. Despite recent advances in materials for use as light-emitting layers, light-absorbing layers or hole-blocking layers, there is a continuing need to find new and improved materials to be used as such components in opto-electroactive devices.